Tensioning device for knitting machines



Apri 13, 1954 v. BUTLER 2,674,867 TENSIONING DEVICE FOR KNITTING MACHINES Filed Dec. 24, 1949 a .25 I1- iii- I 22 1.5 Q J 13 Z2 23 ,Z 4

\, E 20 18 a 15 Z4 INVENTOR.

VAUGHN BUTLER BY ATTORNEYS Patented Apr. 13 1954 TENSIONING' DEVICE FOR KNITTING MACHINES Vaughn Butler, Harriman,

Burlington Mills Corporation,

Tenn, assignor to Greensboro,

N. 0., a corporation of Delaware Application December 24, 1949, Serial N 0. 134,917

2 Claims. 1

This invention comprises improvements in a tensioning device for use in tensioning the fabric being knitted on a circular or spiral knitting machine.

The general object of this invention is to improve the stitch formation in the knitting of circular fabrics and particularly ladies hose from synthetic yarns such as nylon.

An object of this invention is the provision of a structurally simple and easily usable tensioning device for the purpose of effecting uniform loop formation in the knitting of circular knit fabrics, and more specifically for eliminating streaks in circular knit ladies hose from synthetic yarns to insure the elimination of streaks in the fabric.

Other and more detailed objects of this invention will be apparent from the following descriptionof the embodiment thereof illustrated in the accompanying drawings. In the accompanying drawings,

Figure l is a somewhat diagrammatic and perspective view illustrating themanner in which the device of this invention acts to tension circular knit fabric during the knitting-thereof;

Figure 2 is a side elevational view of the tensioning device;

Figure 3 is a similar view to the view of Figure 2;.

Figure 4. is a fragmentary, vertical, central, cross-sectional view with some parts broken away showing the bearing detail of the tensioning device; and

Figure 5- is a cross-sectional, fragmentary view taken on the'line 5-5 of Figure 3, looking in the direction of the arrows.

In the knitting of seamless hosiery from synthet'ic yarns such as nylon there is a tendency to the formation of streaks in the fabric, the elimination of which has been a difiiculty not heretofore successfully overcome. The object of the invention herein disclosed is to provide a simple and practical device by means of which the formation of such streaks is eliminated.

In. accordance with this invention, streak elimination is effected by tensioning the circularly knit fabric during the knitting of the courses thereof by the application of a suitably constructed weighted device to the free end of the fabric so that it is drawn off along the axis of the needle cylinder under tension as it is formed. More specifically this device effects streak elimination by insuring a uniform stitch formation as knitting proceeds.

The knitting of a circular fabric, and especially taken at right angles v ance to the fabric.

ladies hosiery on a circular knitting machine from synthetic yarns which are wire-like in nature, inherently tends to produce a loop formation which to the eye imparts a streaked appear- Synthetic yarns such as nylon are naturally resilient and have a low (:0- efficient of friction so that the bearing of the nylon thread on itself as the result of the interconnected loop formations offers no effective resistance to hold the loops in uniform configuration. In circular knitting with latch needles it is dificult to obtain uniform stitch or loop formation due to the resilient nature of the yarn and its low co-efficient of friction. This tendency to non-uniform loop configuration is also contributed to by the fact that the needles and the sinkers tend to wear in use, imparting a looseness to the mechanical structure which permits the yarn by reason of these inherent characteristics to deviate, although minutely, from the desired loop uniformity. Even though this deviation is minute in character, it is enough in the completed fabric to cause streaks which are classed as undesirable. By properly tensioning the fabric as it is knit all these causes of non-uniformity of loop formation are held to a minimum. The prime purpose of this invention is to provide a practical device for imparting such tension to the fabric.

Referring to the drawings, the device itself is shown as comprising a body H? of sui'licient weight for the purpose. The configuration of this body is not critical, but for obvious reasons the spherical form illustrated is preferable; The sphere 10 has a diametral passage ii extending therethrough, one terminal end of which is threaded to receive the screw threaded ends l2 of a bearing stud I 3. The bearing stud i3 is concentrically telescoped within an annular recess in a sleeve l4. Interposed between the stud l3 and the sleeve I4 is an anti-friction bearing such as the ball bearing [5. It will be recognized that this ball bearing structure is diagrammatically illustrated and may be varied'in detail in accordance with well known practices in the anti-friction bearing art. The sleeve or casing M has an integral concentric boss It on the upper face thereof having a central passage therethrough, the upper end of which is threaded. This serves to provide a simple method of attaching a yoke l8 to the cage It by means of a machine screw H, as clearly illustrated in Figure 4.

The yoke 18 consists of an integral central portion having a pair of divergent arms having their terminal ends l9 (see Fig. 5) bent inwardly in opposed relation. As is clear from Figures 3 and 5, the terminal ends is are transversely grooved so as to be of similar configuration to the interior of a cylindrical spring pressed clamp 20. This clamp is in the form of a longitudinally split tube, as is clear from Figure 3. Quite obviously if the yoke 18 is made of spring metal the di; vergent arms can be separated to permit easy attachment and detachment of the tubular spring 20 thereto.

The tubular spring forms part of a clip or clamp consisting of a pair of plates 21 curved along their upper edges towards each other to provide a clamping jaw. The lower outside edges of the plates 21 are bent inwardly towards each other and then downwardly in more or less parallel relation, as shown in Figure 2, to form pairs of pivot lugs 22 between each pair of which lies a pivot ball 25 which is maintained in proper pivotal relation with the plates by reason of the formation in each of the tips 22 of the plates opposed depressions 23. These pairs of opposed depressions form seats for engaging the pivot balls on opposite sides thereof. The central portions of the plates 2i have downward extensions 24 forming finger pieces by means of which the clamps may have opened against resistance of the tubular spring 20.

It will be readily seen from the above description that the upper opposed clampin edges of the plates 22 can be separated by pressure on the extensions 23 from opposite sides against the resistance of the spring 38 so that the edge of the tubular knit fabric F can be gripped therebetween.

The manner in which this device is used will be clear from Figure 1. The needles of a circular or spiral knitting machine are diagrammatically illustrated at N in this figure and as lying at the upper end of the knitting machine cylinder C down through which the tubular fabric F progresses as its length increases. In the use of this device in the knitting of ladies hosiery when the welt is completed the machine is stopped either manually or automatically and the knitting machine head is raised. The operator then reaches down into the cylinder C and pulls the knitted welt back up through the needles so that the free end of the welt extends upwardly. The tensioning device of this invention is then passed downwardly through the open upstanding end of the welt and the edges of the welt are folded inwardly and positioned between the clamping jaws of the plate 2:, which of course have been opened by pinching on the extensions 24. The clamp is then released so that it attaches itself to the free or beginning end of the Welt, and the device is then lowered back down through the cylinder C so that it is held suspended by the welt. The machine is started up and as the boot, in the case of a ladies stocking, is knit the fabric will be drawn downwardly under the tension of the weight of the device. In one practical form for use on commonly used circular knitting machines the total weight of the device may be of the order of three-quarters of a pound. Due to the tension in the fabric caused by the weight of the device, a more uniform stitch is formed and once properly formed remains thus due to this tension in the fabric caused by the device suspended thereby.

The anti-friction connection between the weighted body it and the supporting structure therefor is provided to keep the fabric being knit from twisting when the machine is started and when the cylinder of the machine is oscillating during the production of the heel and toe. The inertia of the body It) with the anti-friction support therefor prevents that body from tending to rotate, with the result that the fabric being knitted is not twisted as an incident to the normal operation of machines of this type. When the knitting of the fabric has been completed the tension device can easily be detached by again applying pressure to the tension or finger pieces 24, which opens the clamp jaws.

As will be obvious to those skilled in the art, this tension device acts throughout the knitting of the fabric to impart a constant and uniform tension thereto. It will be appreciated that the utility of this device is increased by reason of the fact that it may be used in conjunction with circular knitting machines commonly used today without requiring other than the conventional manner of operation of the machines. The weight may be quickly attached at the proper time so that the idle time of the machine by reason of the use of the device is of very short duration.

Those skilled in this art will readily appreciate that variations in the details of construction and use of this device may be practiced without departing essentially from the construction illustrated herein, and I do not, therefore, desire to be strictly limited to the particular embodiment selected for illustrative purposes, but rather to the scope of claims granted me.

What is claimed is:

1. A tensioning device of the type described comprising a body of predetermined weight, a stud shaft secured to said body, a bearing cage disposed concentrically with said stud shaft, an anti-friction bearing interposed between said stud shaft and cage, and a clamp secured to said cage.

2. In the combination of claim 1, saidclamp including a pair of pivotally interconnected spring pressed clamping members and a yoke for attaching said clamping members to said cage.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 317,773 Hayden May 12, 1885 458,710 Thurstensen July 28, 1891 623,539 Gulich Apr. 25, 1899 1,978,957 Pardieck Oct. 30, 1934 2,250,731 St. Pierre July 29, 1941 2,521,258 Scmotan Sept, 5, 1950 FOREIGN PATENTS Number Country Date 554,809 Germany July 12, 1932 

